interface Com {
	int add(int a,int b);
}
abstract class A{
	abstract int add(int a,int b);
}
class B extends A implements Com{
	public int add(int a ,int b) {
		return a+b;
	}
}
public class EE {
	public static void main(String args[]) {
		B b = new B();
		Com com = b;
		System.out.println(com.add(12,6));
		A a = b;
		System.out.println(a.add(10,5));
	}
}
